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As isolated microgrids with diesel generators have difficulties meeting the power fluctuations caused by intermittent renewable energy sources (RES), a combination method, which splits a high power hydraulic power generation system (HPGS) in wave energy converter (WEC) into multiple low power HPGSs, was implemented in order to reduce the magnitude of fluctuations in grid connections. A reliable grid connection based on a DC voltage source mode inverter was proposed for multiple HPGSs. A simulation model for an isolated microgrid was developed, which included WEC, HPGS, power electronic conversion system (PECS), and diesel generator. Comparative tests were carried out between multiple HPGSs and single HPGS and feasibility of connecting a large-scale WEC to isolated island microgrid was verified. Multiple HPGSs have been shown to have a lower impact on the grid when operating at the same total rated power of the generator. The research results have been applied to large-scale WECs such as the "Zhou Shan Hao", which has a total power of 500 kW, establishing the groundwork for connecting large-scale WECs to isolated microgrid on islands powered by diesel generators. [ABSTRACT FROM AUTHOR]

Abstract According to the characteristics of the hydraulic power generation system (HPGS), HPGS can be directly fed into a DC nano grid through using an uncontrolled rectifier. However, determined only by the DC voltage, the motor speed of the HPGS is a constant rather than an optimal speed, whose curve is unknown yet during the whole power generation process. In order to realize the control of the HPGS's motor speed and reduce the armature current harmonics, a pulse width modulation (PWM) rectifier topology is introduced to replace the uncontrolled rectifier. First, the principle of the PWM rectifier is studied. Second, a control structure of this PWM rectifier is established, including a current decoupling control in the inner loop and a speed feedback control in the outer loop. After this, a maximum efficiency converting control strategy is adopted. Based on the above, the simulation model of the PWM rectifier which was fed into DC nano grid was established and a series of experiments were carried out. The experimental results show that the armature current waveform is sine wave and its rectification is flexible. Furthermore, the maximum efficiency converting control strategy is realized with HPGS's always working at the optimal speed curve. Highlights • HPGS is separated from hydraulic energy converting system of WEC. • HPGS feeds into DC nano grid. • The mathematical model of PWM rectifier for HPGS is established. • The maximum efficiency converting control strategy for HPGS is proposed. • An optimal speed curve of HPGS is concluded from speed experiments. [ABSTRACT FROM AUTHOR]

To find an efficient and economic way to convert wave energy, a one-base multi-buoy offshore floating wave energy converter Sharp Eagle Wanshan is designed, consisting of four absorbing buoys, one semi-submersible barge, and other components. The working principle of the device is described in this paper. An experiment of a 1:13.78 model machine was carried out to test the hydrodynamic performance of the device and make an initial evaluation for the design The influence of wave period, wave height, work load and wave direction was tested. After construction, two-stage open sea tests have been finished in the waters near Wanshan Islands from November 2015 to June 2016. The device showed great power generation capacity with total generated output of 30530.57 kWh, and largest daily generation of 1847.09 kWh. During the open sea tests, the energy conversion efficiency was measured, and results show that capture width ratio of Wanshan remains higher than 20% in the wave period between 4 and 6.5 s and wave height range of 0.6–1.8 m. After operating in a wide range of conditions, including a tropical storm on May 27, amounts of tests data, experiences and lessons have been obtained and will be summed up and presented in the paper. [ABSTRACT FROM AUTHOR]

Punch sticking is a complex phenomenon influenced primarily by particle size, tooling surface roughness, tooling design, and tooling construction material. When particle and environmental factors are controlled, compaction pressure has a distinct effect on punch sticking behavior for a given active pharmaceutical ingredient (API). This research focuses on the effect of compaction pressure on punch sticking using 5 compounds with different sticking propensities. The results collectively show that sticking tends to be more problematic under higher compaction pressures and for more ductile compounds. This is attributed to the greater punch surface coverage by the API and the stronger cohesion of API to the existing API layer on the punch. [ABSTRACT FROM AUTHOR]

A dynamically stretchable solid state supercapacitor using graphene woven fabric (GWF) as electrode materials is designed and evaluated. The electrode is developed after GWF film is transferred onto a pre-stretched polymer substrate. Polyaniline is deposited covering the GWF film through in-situ electropolymerization to improve the electrochemical properties of the electrode. The supercapacitor is assembled in sandwich structure and packaged in polymer and its electrochemical performance is investigated under both static and dynamic stretching modes. The stretchable supercapacitors possess excellent static and dynamic stretchability. The dynamic strain can be up to 30% with excellent galvanic stability even under high strain rates (up to 60%/s). [ABSTRACT FROM AUTHOR]

Abstract: Direct tensile tests of double walled carbon nanotube (DWCNT) membranes with thickness of 40–80nm were performed using a micro-stress-strain puller. The tensile strength and Young’s modulus are 4.8E2–8.4E2MPa and 4.4–8.8GPa, respectively. The deformation and fracture processes were analyzed using the stress vs. strain curves, and SEM observations of the fracture surface of a membrane. The membrane experienced elastic strain and plastic strain during tensile-loading to fracture, and the plastic process is due to the real plastic deformation of the membrane and the slippage between the DWCNT bundles. Cracks occur and spread during the tensile test which causes the membrane to be mangled. With these excellent mechanical properties, the DWCNT membranes can be used in nanotube-reinforced composites. [Copyright &y& Elsevier]

Abstract: The mechanical properties of well-aligned double-walled carbon nanotube (DWNT) strands with diameters of 3–20μm and lengths of ∼10mm were measured using a stress–strain puller. The average tensile strength and Young’s modulus of the tested strands are 1.2GPa and 16GPa, respectively. Deformation and fracture processes of these samples are discussed. The tensile strength and Young’s modulus of an individual DWNT bundle were estimated, with values comparable to those of SWNT bundles. The superior mechanical strengths of our as-prepared DWNT strands are expected to give them potential as a high-strength material and a reinforcement in composites. [Copyright &y& Elsevier]

Celecoxib, an anti-inflammatory drug for pain and arthritis, is currently only available in capsule form. To reduce the onset time for a faster action and to lower the manufacturing cost, the tablet dosage form is more preferred. However, the commercial celecoxib (Form III) is not suitable for direct compression (DC) tablet manufacture due to poor flow, low bulk density, and tablet lamination. In this work, we overcome these challenges using a pharmaceutically acceptable dimethyl sulfoxide (DMSO) solvate of celecoxib. Aided with the DMSO solvate, an acceptable DC tablet formulation was successfully developed to manufacture tablets containing 200 mg celecoxib, with satisfactory manufacturability, disintegration, and in vitro dissolution performance. [ABSTRACT FROM AUTHOR]

This paper proposes an ultrasound imaging algorithm based on sub-beamformer and multi-apodization with cross-correlation (SUB-MAX), aiming to achieve high resolution close to the minimum variance (MV) beamforming with low complexity and to enhance image contrast while maintaining background quality. The output of two (N /2)-element DAS beamformers with asymmetric phase centers is subtracted, resulting in a large drop in the main-lobe amplitude, while the sidelobe maintains a relatively high amplitude level. Inspired by this characteristic, the coefficients with opposite trends compared with the subtracted output are obtained and fused with the normalized cross-correlation (NCC) weighting matrix acquired by using multi-pair received apodization, the proposed SUB-MAX obtains a new weighting matrix to weight the output of the DAS beamformer. For ats_wire point targets, the average full-width at half-maximum (FWHM) of SUB-MAX compared with DAS, DMAS, CF, and MAX decreases by 52.7%, 43.5%, 33.3%, and 52.7%, respectively. For geabr_0 cysts, the average contrast ratio (CR) of SUB-MAX compared with DAS, MV, DMAS, and CF increases by 57.7%, 86.8%, 2.5%, and 14.4%, respectively. Experiments on rat_tumor dataset also indicate that SUB-MAX has a superior comprehensive imaging performance. The experimental results indicate that the superior comprehensive imaging performance of the proposed SUB-MAX is expected to be suitable for real-time imaging systems due to its non-reliance on covariance matrix inversion. [ABSTRACT FROM AUTHOR]

Electrochemical anisotropic etching, along with prior cathodic polarization during anodic etching, is used to form homogeneous antireflective (AR) structures on metal surfaces. Further electrophoretic deposition forms graphene oxide (GO) nanostructures. The graphene-based AR coating is achieved by electrochemical reduction of GO. Optical metal surfaces with high efficiency of light absorption and low reflectivity are obtained. Our results demonstrate the potential use of graphene in anti-reflection coating. [ABSTRACT FROM AUTHOR]

Abstract: The recyclability of carbon nanotube (CNT) sponges in terms of oil absorption was studied. The sorption capacities of these sponges are greater than 100gg–1 for many organics and oils with viscosities of 3–200cP, and they maintain sorption capacities of 20–40gg–1 after 10 cycles of absorption. About 98% of absorbed oil can be recovered by squeezing or converted to heat by directly burning the oil within the sponges. The sorption process has been described by a second-order kinetic model. The results demonstrate that CNT sponges are promising oil sorbents with good recyclability. [Copyright &y& Elsevier]

Abstract: Large area (the order of centimeters), flexible thin films of amorphous carbon were prepared on copper foils by an ethanol flame synthesis method. The carbon films exhibit high transmittance in the visible and near infrared range (up to 90% at 550nm). Schottky diodes formed by combining the carbon films with n-type silicon wafers show high on/off ratio (up to 150) photocurrents at air-mass 1.5 and illumination intensity of 100mW/cm2. [Copyright &y& Elsevier]

Abstract: Carbon nanotube (CNT) arrays doped with nitrogen were synthesized using chemical vapor deposition by pyrolysis of xylene/pyridine and ferrocene with a modified precursor feeding technique. The system produced a gradient of nitrogen concentration that modified the CNTs from a hollow cylinder to a bamboo-shaped structure which contains a series of compartments whose lengths are gradually reduced as the nitrogen concentration increases. [Copyright &y& Elsevier]

Abstract: Field emission properties of partly Fe-filled carbon nanotubes (FCNTs) treated with different plasmas have been studied. Super low turn-on (0.24V/μm) and threshold (0.6V/μm) electric fields are identified upon nitrogen plasma treatment for 60min. The field-enhancement factor, as high as 4.8×104, can be attributed to the plasma-induced structural defects and the unique characteristics of thin walled FCNTs with filled Fe nanowires. A model has been proposed to understand the effects of plasma on the CNTs. [Copyright &y& Elsevier]

Abstract: Silicon nanowire (SiNW) arrays were fabricated on silicon wafers by the metal-assisted chemical etching method. Varied average diameters of SiNW arrays were realized through further treatment in a mixed agent of HF and HNO3 of certain concentrations. After the treatment, there were more than 93% SiNWs with diameters smaller than 100nm. The tip of each SiNW was subsequently wrapped with multi-walled carbon nanotubes (MWCNTs) with chemical vapor deposition method. The as-fabricated MWCNT/SiNW arrays were fabricated into electric field emitters, with turn-on field of 2.0V/μm (current density: 10μA/cm2), much lower than that of SiNW array (5.0V/μm). The turn-on electric field of MWCNT/SiNW array decreased with the decreasing of the average diameter of SiNWs, indicating the performance of the field emission is relative to the morphology of SiNWs. As the SiNW array is uniform in height and easy to fabricate, the MWCNT/SiNW array shows potential applications in flat electric display. [Copyright &y& Elsevier]

Abstract: Carbon-based photovoltaic cells (PVCs) have attracted a great deal of interest for both scientific fundamentals and potential applications. In this paper, applications of various carbon materials in PVCs, especially in silicon-based solar cells, organic solar cells and dye-sensitized solar cells, are reviewed. The roles carbon materials played in the PVCs are discussed. Further research on solar cells comprised solely of carbon is prospected. [Copyright &y& Elsevier]

Abstract: The filling rate of Fe nanowires in carbon nanotubes (CNTs) was improved by a post-treatment which involved annealing and magnetic separation. The annealing process transformed γ-Fe to ferromagnetic α-Fe, resulting in α-Fe-filled CNTs with improved magnetic properties. The Fe-filled CNTs were then separated from those unfilled CNTs due to the different attractive forces under magnetic field. Thermal gravimetric analysis (TGA) revealed that the purity of CNTs was improved after magnetic separation and the filling rate can be up to 40.0wt.%, which is increased about 8.1% comparing with annealed CNTs. The saturation magnetization of CNTs reached 31.45emu/g after magnetic separation. [Copyright &y& Elsevier]

As a kind of flexible membrane structure, the flexible bag-type wave energy converter (WEC) is currently in the conceptual development stage. This paper presents a novel type of water-filled submerged flexible bag WEC that has successfully generated electricity in a laboratory environment. Experimental studies have been conducted to investigate the hydrodynamic response of the flexible bag and the optimal resistance damping of the power take-off (PTO). The experimental results show that the average displacement of the PTO and power output are nonlinear for different wave heights. Furthermore, the capture width ratio (CWR) of the WEC varies depending on the wave period. The optimal resistance damping for this physical model has been determined to be 80 Ω. These findings can serve as a validation for future numerical simulations, and additional experimental studies will be carried out to optimize the structure of the WEC and enhance its energy conversion efficiency. [ABSTRACT FROM AUTHOR]

Appropriate selection of excipient grade during tablet formulation development depends on thorough knowledge in their compaction and flow properties. Each chemically unique pharmaceutical excipient is usually available in several commercial grades that are widely different in powder properties, which influence their performance for a specific formulation application. In this work, 11 grades of mannitol were systematically characterized, in terms of their particulate, flow and tableting properties, and compared against 5 grades of lactose. Principal component analysis (PCA) identified significant correlations among selected variables, such as particle size, surface area, flowability, wall friction, plasticity parameter, tensile strength, and tablet brittleness. PCA also revealed similar grades of the two excipients, which may be used to select replacement grade, if needed, based on similarity in their overall properties. [ABSTRACT FROM AUTHOR]

A spindle-like hierarchical carbon structure of submicron dimensions is synthesized by floating catalytic deposition using a polyhydroxyalkanoate (PHA)/ferrocene/chloroform precursor. The electron microscopic morphology characterizations demonstrate that as-prepared carbon micro-spindle (CMS) comprises three components: two symmetric carbon cones formed by curved graphitic filaments consisted of randomly orientated graphene layers, and one middle catalyst plate with a rough surface. CMSs only grow on large catalyst plates with complicated surface microstructures. Chlorine is employed to tune the crystallinity of the catalyst, leading to a rough surface of the catalyst plate. Graphene layers are deposited parallel to the catalyst surface. Carbon spindles sharing the same catalyst plate form CMS clusters. The electrochemical performance of CMSs is further investigated, showing good capacitance properties with excellent cycling stability, indicating its application potential in energy storage devices. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (RGO)/Si Schottky diode has been fabricated by a simple drop-casting/annealing process. Common combustible and/or toxic gases including CH 4 , O 2 , CO, NO 2 , NO, and SO 2 were employed to evaluate the detection performance of such device. The relationship between current response and gas flow rate, concentration, bias voltage as well as operating time has been systematically studied, and the results indicated that the RGO/Si-based device is selective to gases like NO 2 and NO. In some cases ( i.e. flow rate detection), however, the current response for one gas is completely contrary to others, presumably due to the oxygen functional groups (OFGs) presiding on the surface of reduced graphene oxide. Finally, the effects of OFGs on the gas detection performance of RGO/Si-based devices were thoroughly discussed. [ABSTRACT FROM AUTHOR]

Abstract: Large-scale few-layer graphene (FLG) films were prepared by an industrial single-roller melt spinning technique based on molten alloy quenched carbon self-segregation using nickel and carbon as precursors. A formation mechanism of FLG based on rapid diffusion and non-equilibrium segregation of carbon is discussed. This ultra-fast thin film preparation technique can be extended and used to produce ultrathin sheets of two-dimensional materials other than graphene. [Copyright &y& Elsevier]

Abstract: We report the fabrication of hybrid films of graphene and monolayer titania using a simple electrostatic self-assembly method. Ultraviolet (UV) responses of the hybrid films based on the graphene–titania structure were investigated. We observed that the resistance of the graphene–titania hybrid increased exponentially with UV irradiation time and decreased exponentially when UV was turned off. Time constants of the order of hundreds of seconds were identified and found to be sensitive to the gas environment of graphene. The UV response as well as the time constant is tunable by varying the number of titania layers. Our results confirmed that UV irradiation played a significant role in the resistance modulation of graphene as well as graphene–titania hybrid films. [Copyright &y& Elsevier]

Abstract: We have investigated the production of nitrogen-doped graphene (NG) from liquid acetonitrile and demonstrated that there is a critical feed rate of acetonitrile for the growth of NG. Graphene sheets could be obtained at feed rate lower than 0.08mL/min. While at 0.08mL/min or above, only polycrystalline carbon films could be obtained. Therefore, selective synthesis of NG or carbon films could be achieved by simply altering the feed rate of acetonitrile, which provides an effective way to control the growth of NG sheets. Furthermore, NG sheets (0.06mL/min sample) and carbon films (0.08mL/min sample) exhibit light transmittance of ∼90% and 70% at 550nm, and sheet resistance of ∼1400 and 1000 Ω/sq, respectively, showing their potential applications in carbon-based nanoelectronics. [Copyright &y& Elsevier]

Abstract: Graphene, a new member of carbon family, has been prepared, characterized and used as adsorbent to remove phenol from aqueous solution. The effect parameters including pH, dosage, contact time, and temperature on the adsorption properties of phenol onto graphene were investigated. The results showed that the maximum adsorption capacity can reach 28.26mg/g at the conditions of initial phenol concentration of 50mg/L, pH 6.3 and 285K. Adsorption data were well described by both Freundlich and Langmuir models. The kinetic study illustrated that the adsorption of phenol onto graphene fit the pseudo second-order model. The thermodynamic parameters indicated that the adsorption of phenol onto graphene was endothermic and spontaneous. [Copyright &y& Elsevier]

Abstract: N-doped carbon thin films (N-CFMs) on copper foils are synthesized by using acetonitrile (CH3CN) as liquid carbon and nitrogen precursors in a chemical vapor deposition system. Effect of acetonitrile feeding amount on the optical transmittance and electrical conductivity of N-CFMs are investigated. It is found that both the transmittance (from ∼41% to ∼75%) and sheet resistance (from ∼700Ω/sq to ∼2000Ω/sq) increases with the decrease of acetonitrile feeding amount (from 200μL to 10μL). Schottky junction solar cells based on n-type silicon and as-synthesized N-CFMs demonstrate power conversion efficiencies of up to ∼1.55%, showing their potential applications in photovoltaic areas. [Copyright &y& Elsevier]

Abstract: Aims: Adipose tissue plays an important role in the pathogenesis of insulin resistance, obesity, and Type-2 diabetes. Human adipocytes express abundant cholesteryl ester transfer protein (CETP). However, the function and role of CETP in regulating lipoprotein metabolism are mostly unknown. In this study, we examined whether CETP affected the insulin-mediated responses in adipocytes. Main methods: Because mouse 3T3-L1 preadipocytes do not express CETP, we established a stable cell line expressing human CETP by transfecting the cells with pcDNA3.1/human CETP. We used a standard approach to differentiate the cells into mature adipocytes, and we examined the cholesterol balance and insulin responses. Key findings: The human CETP stable cell line expressed stable levels of CETP without affecting the expression of either peroxisome proliferator-activated receptor-gamma (PPARγ) or glucose transporter-4 (GLUT4) throughout cell differentiation. CETP expression significantly increased the level of both total and free cholesterol in the mature adipocytes. Upon insulin stimulation, CETP expressing cells had significantly higher protein kinase B (Akt) phosphorylation and 2-3H-deoxyglucose uptake, as compared with 3T3-L1 cells and cells transfected with control vector. Significance: Human CETP expression increased cellular cholesterol levels and enhanced insulin-stimulated Akt phosphorylation and glucose uptake in adipocytes. Thus, CETP may modulate glucose metabolism and insulin action in addition to its effects on lipoprotein metabolism. [Copyright &y& Elsevier]

Abstract: Carbon nanotube films with high nanotube loading were prepared using a vacuum filtration method and their photovoltaic properties as semi-transparent conducting electrodes in nanotube-silicon heterojunction solar cells were investigated. The correlation between the power conversion efficiency of the solar cells and the figure of merit (FM) of the films were obtained. The maximum efficiencies (up to 1.5%) were found for those cells using the films with highest FMs and transmittances. For comparison, the photovoltaic performance of a self-assembled nanotube thin film of high transmittance (91%) was tested and the corresponding solar cell showed a conversion efficiency of ∼4%. This work provides guidance for future improvement on the photovoltaic properties of nanotube films as window electrode materials. [ABSTRACT FROM AUTHOR]

Abstract: A general strategy for in situ synthesis of open-ended, thin-walled carbon nanotubes (CNTs) filled with long ferromagnetic (FeNi, FeCo, FeCoNi, etc.) nanowires is proposed. The key feature of this strategy is the introduction of Cl-contained benzene (e.g. trichlorobenzene) as carbon precursor. Size-dependent etching effect of Cl radicals on the sidewalls of CNTs is proved by theoretical calculations. As-prepared thin-walled FeNi-filled CNTs (FeNi–CNTs) show much lower turn-on field of 0.30V/μm (at 10μA/cm2) and lower threshold field of 0.65V/μm (at 1.0mA/cm2) than those of thick-walled counterparts. Moreover, as-prepared thin-walled FeNi–CNTs show good field-emission stability at a low vacuum level (10−6 Torr). The enhanced field-emission performance can be attributed to a combined contribution of open-end tips, thinner sidewalls and metal nanowire fillings. [Copyright &y& Elsevier]

Abstract: Two different growth modes of carbon nanotubes (CNTs) are identified in ethylene chemical vapour deposition (CVD) using SiO2 as support. With a series of electron microscopy observations, we have found that small-diameter nanotubes favor a root-growth mechanism on nanoporous SiO2 support, while nanotubes with larger diameters prefer a tip-growth. The dependence of growth mode on tube diameter is explained in terms of the porosity of the support and the size distribution of the catalyst. Our results provide clues to control growth of CNTs and obtain well-organized nanotube structures. [Copyright &y& Elsevier]

Abstract: Ferromagnetic buckypaper of carbon nanotubes filled with Fe nanowires (Fe-CNT) was in situ synthesized without using any surfactants or acid treatment. As-synthesized Fe-CNT buckypaper shows strong anisotropic behavior, which can be attributed to the different response of Fe-nanowires inside carbon nanotubes with high aspect ratio in different applied magnetic field. [Copyright &y& Elsevier]

Abstract: Iron oxide nanoparticles have been produced on the top surface of aligned multi-walled carbon nanotubes by CO2 laser processing. They were characterized to be Fe2O3 nanoparticles by X-ray photoelectron spectroscopy, X-ray diffraction and high resolution scanning electronic microscopy. Absorption bands in the visible region were found to be redshifted compared with the absorption of Fe2O3 nanoparticles prepared by traditional chemical methods. Photoluminescence from these Fe2O3 nanoparticles shows a broad emission band in the near infrared region for both excitations at 514 and 633nm. Particle size is considered to be responsible for the unique optical properties of the Fe2O3 nanoparticles. [Copyright &y& Elsevier]

Abstract: A novel process for in situ filling of long continuous FeNi nanowires into thin-walled carbon nanotubes (CNTs) is reported, which is achieved by simply using chlorine-contained benzene, C6H3Cl3, as the carbon precursor. The length of FeNi nanowires encapsulated in CNTs is up to ∼4μm, which is increased by an order of magnitude compared with those of previous reports (lengths <500nm). Magnetic measurements on the sample show typical ferromagnetic properties with a Curie temperature (Tc ) of 640°C. Theoretical calculations show that this kind of materials is promising and can be used as an effective microwave absorber with a thinner coating layer. [Copyright &y& Elsevier]

Abstract: In this paper, double-walled carbon nanotube (DWNT) bundles can be transformed into multi-walled carbon nanotubes (MWNTs) by electric current treatment in vacuum. The morphology of the transformed MWNTs shows an obvious dependence on power density of the current, which changes from partly transformed MWNTs to collapse MWNTs with the increase of power density. The process of this structural transformation follows the tendency of forming more stable structures, and can be ascribed to the sequential coalescence of DWNTs inside the bundles. [Copyright &y& Elsevier]